refactor: 将客服后端重构为宿主可嵌入模块

- 注入数据库、运行时配置、统一响应、文件存储和平台 AI 能力，补充业务读写工具与客户快捷操作契约。

- 移除模块内重复的组织、客户、工单、标签、技能、旧工作流、MCP 和迁移实现，将身份权限与业务主体交由宿主管理。

- 使用 libSQL 重构向量存储，并完善图片消息、访客身份、排队调度、企业微信和支持聊天页面。

- 统一 HTTP、DTO 与 WebSocket 的 snake_case 协议，补齐模块初始化、业务动作和公共载荷等回归测试。

internal/services/knowledge_base_service_test.go

@@ -1,12 +1,8 @@
 package services
 
 import (
-	"encoding/json"
-	"strings"
 	"testing"
 
-	"code.tczkiot.com/wlw/ai-agent/internal/ai/workflow/dsl"
-	workflowregistry "code.tczkiot.com/wlw/ai-agent/internal/ai/workflow/registry"
 	"code.tczkiot.com/wlw/ai-agent/internal/models"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/dto/request"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/enums"
@@ -27,51 +23,6 @@ func TestBuildKnowledgeBaseModelUsesLowerDefaultScoreThreshold(t *testing.T) {
 	}
 }
 
-func TestDeleteKnowledgeBaseRejectsWorkflowDraftReference(t *testing.T) {
-	setupKnowledgeBaseServiceTestDB(t)
-	kb := createKnowledgeBaseServiceTestBase(t, "Referenced KB")
-	otherKB := createKnowledgeBaseServiceTestBase(t, "Other KB")
-	createKnowledgeBaseServiceTestWorkflow(t, "Support Workflow", knowledgeBaseServiceTestWorkflowDefinition([]int64{12, otherKB.ID}))
-	createKnowledgeBaseServiceTestWorkflow(t, "Knowledge Workflow", knowledgeBaseServiceTestWorkflowDefinition([]int64{12, kb.ID, otherKB.ID}))
-
-	err := KnowledgeBaseService.DeleteKnowledgeBase(kb.ID)
-	if err == nil {
-		t.Fatal("DeleteKnowledgeBase() error is nil, want referenced workflow error")
-	}
-	if got := err.Error(); !strings.Contains(got, "Knowledge Workflow") {
-		t.Fatalf("DeleteKnowledgeBase() error = %q, want workflow name", got)
-	}
-	if repositories.KnowledgeBaseRepository.Get(sqls.DB(), kb.ID) == nil {
-		t.Fatal("knowledge base was deleted despite workflow reference")
-	}
-}
-
-func TestDeleteKnowledgeBaseRejectsWorkflowVersionReference(t *testing.T) {
-	setupKnowledgeBaseServiceTestDB(t)
-	kb := createKnowledgeBaseServiceTestBase(t, "Version KB")
-	workflow := createKnowledgeBaseServiceTestWorkflow(t, "Published Workflow", knowledgeBaseServiceTestWorkflowDefinition([]int64{999}))
-	raw, err := json.Marshal(knowledgeBaseServiceTestWorkflowDefinition([]int64{kb.ID}))
-	if err != nil {
-		t.Fatalf("marshal workflow version definition: %v", err)
-	}
-	if err := repositories.AIWorkflowVersionRepository.Create(sqls.DB(), &models.AIWorkflowVersion{
-		WorkflowID: workflow.ID,
-		Version:    1,
-		Status:     enums.StatusOk,
-		Definition: string(raw),
-	}); err != nil {
-		t.Fatalf("create workflow version: %v", err)
-	}
-
-	err = KnowledgeBaseService.DeleteKnowledgeBase(kb.ID)
-	if err == nil {
-		t.Fatal("DeleteKnowledgeBase() error is nil, want referenced workflow version error")
-	}
-	if got := err.Error(); !strings.Contains(got, "Published Workflow") {
-		t.Fatalf("DeleteKnowledgeBase() error = %q, want workflow name", got)
-	}
-}
-
 func TestDeleteKnowledgeBaseCascadesContentWhenNotReferenced(t *testing.T) {
 	setupKnowledgeBaseServiceTestDB(t)
 	kb := createKnowledgeBaseServiceTestBase(t, "Delete KB")
@@ -119,67 +70,12 @@ func setupKnowledgeBaseServiceTestDB(t *testing.T) {
 	if err != nil {
 		t.Fatalf("open sqlite db: %v", err)
 	}
-	if err := db.AutoMigrate(&models.KnowledgeBase{}, &models.KnowledgeDocument{}, &models.KnowledgeFAQ{}, &models.KnowledgeChunk{}, &models.AIAgent{}, &models.AIWorkflow{}, &models.AIWorkflowVersion{}); err != nil {
+	if err := db.AutoMigrate(&models.KnowledgeBase{}, &models.KnowledgeDocument{}, &models.KnowledgeFAQ{}, &models.KnowledgeChunk{}, &models.AIAgent{}); err != nil {
 		t.Fatalf("auto migrate: %v", err)
 	}
 	sqls.SetDB(db)
 }
 
-func createKnowledgeBaseServiceTestWorkflow(t *testing.T, name string, definition dsl.Definition) *models.AIWorkflow {
-	t.Helper()
-	raw, err := json.Marshal(definition)
-	if err != nil {
-		t.Fatalf("marshal workflow definition: %v", err)
-	}
-	item := &models.AIWorkflow{
-		Name:            name,
-		Status:          enums.StatusOk,
-		DraftDefinition: string(raw),
-	}
-	if err := repositories.AIWorkflowRepository.Create(sqls.DB(), item); err != nil {
-		t.Fatalf("create workflow: %v", err)
-	}
-	return item
-}
-
-func knowledgeBaseServiceTestWorkflowDefinition(knowledgeBaseIDs []int64) dsl.Definition {
-	return dsl.Definition{
-		SchemaVersion: dsl.SchemaVersion,
-		Nodes: []dsl.Node{
-			{
-				ID:   "start_1",
-				Type: workflowregistry.NodeTypeStart,
-			},
-			{
-				ID:   "retrieve_1",
-				Type: workflowregistry.NodeTypeKnowledgeRetrieve,
-				Data: dsl.NodeData{
-					Config: mustKnowledgeBaseServiceTestJSON(map[string]any{"knowledgeBaseIds": knowledgeBaseIDs}),
-					InputsValues: map[string]dsl.Value{
-						"query": dsl.RefValue("start_1", "userMessage"),
-					},
-				},
-			},
-			{
-				ID:   "end_1",
-				Type: workflowregistry.NodeTypeEnd,
-			},
-		},
-		Edges: []dsl.Edge{
-			{SourceNodeID: "start_1", TargetNodeID: "retrieve_1"},
-			{SourceNodeID: "retrieve_1", TargetNodeID: "end_1"},
-		},
-	}
-}
-
-func mustKnowledgeBaseServiceTestJSON(value any) json.RawMessage {
-	raw, err := json.Marshal(value)
-	if err != nil {
-		panic(err)
-	}
-	return raw
-}
-
 func createKnowledgeBaseServiceTestBase(t *testing.T, name string) *models.KnowledgeBase {
 	t.Helper()
 	item := &models.KnowledgeBase{